Astral Hydra

Hold Breath. The hydra can hold its breath for 1 hour.

Multiple Heads. The hydra has five heads. While it has more than one head, the hydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

Whenever the hydra takes 25 or more damage in a single turn, one of its heads dies. If all its heads die, the hydra dies.

At the end of its turn, it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The hydra regains 10 hit points for each head regrown in this way.

Reactive Heads. For each head the hydra has beyond one, it gets an extra reaction that can be used only for opportunity attacks.

Wakeful. While the hydra sleeps, at least one of its heads is awake.

Multiattack. The hydra makes as many bite attacks as it has heads and one special breath attack.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 10 (1d10 + 5) piercing damage.

Breathe Effects. The Astral Hydra breathes one of the following magical effects at a chosen target, choosing one to three targets it can see within 120 feet of it:

1. Charm Ray. The targeted creature must succeed on a DC 16 Wisdom saving throw or be charmed by the Astral Hydrafor 1 hour, or until the Astral Hydra harms the creature.

2. Paralyzing Ray. The targeted creature must succeed on a DC 16 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

3. Fear Ray. The targeted creature must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

4. Lightning Breath. The Astral Hydra exhales lightning in a 90-­foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking  (4d10) lightning damage on a failed save, or half as much damage on a successful one.
5. Fire Breath. The Astral Hydra exhales fire in a 20-foot cone. Each creature in that area must make a DC 21 Dexterity saving throw, taking 25 (6d6) fire damage on a failed save, or half as much damage on a successful one.